Re: Screw Conveyor Questions
Freshly graduated eh :-)
Did you cover bulk materials handling in your course?
1) this may not have been the best forum to start in, but anyway maybe Lyn will pick up on it.
2) how long is your screw? Rate (te/hr) and length determine power.
3) inclination is usually determined by layout. So where is the feed material coming from and how high is the feed point to the furnace.
4) there are wood chips and wood chips. What's the density (kg/m3) and particle size distribution.
But why are you designing this screw conveyor? Do you intend to make it yourself? It most cases you buy one from a specialist manufacturer ■
More Data
First , yes I am fresh graduate, i work in hvac and i am helping my brother in his project. The data are the following:
- We have to move the wood chips to a 5m height
- The density is between 10 to 30 lbs/ft^3, I have chosen 10 ( I am using matin sprocket so its in table 1-2 page H16.
Particles from 10 to 45 mm - lump size 63 mm
- The woodchips are to be put in a tank in the ground, but i am thinkin that i have to change it.
- in the calculation the screw is 11m long if its' inclined 20
- 7 m if 45, i think there is a problem using the longer one, but my main concern is about the power, are the figures logical?
- You didn't answer me about the precautions to take in case of a fire catching the material that are veing loaded in the furnace.
- Given the additional data, i repeat the same questions again , concerning diameter power and inclination.
- what type of scews is recommended, and what is preferable material if i want to do the hopper.
Waiting your reply ■
Conveying Wood Chips.
This is not an easy one to deal with because of the danger of jamming with wood chips and the length of conveyor required. The capacity of a screw conveyor falls off very rapidly at an inclination greater than 30 degrees to the horizontal and an intermediate bearing is not practical. I would not recommend a screw conveyor for the job without very special design considerationas it bristles with possible problems. Use an inclined belt. The feed hopper then needs a good design, so I would recommend that you study hopper flow theory. ■
Wood Chip Conveying
An alternative solution could be to use a drag chain conveyor .
A vexing problem with screws with granular material is the risk of wedging of small fragments between screw flight edge and screw shell .
A drag chain is more flexible and tolerant .
Incidentally - your feed rate is probably 160 Kg/hr and not 160 Kg/sec . ■
Screw Conveyor Questions
Dear I would appreciate any help !!!!
I am trying to design a screw conveyor feeding a furnace that is used to heat a school. The screw conveyor will transfer wood chips. I have the following questions.
It should feed 160 kg/s. Heating Capacity of the furnace 350KW.
I have used the procedure in Martinsprocket catalogue
1- The diameter is 12 or 14" in my calculation, is that normal?
2- The power required is 0,5 kw is that normal? Is it enough?
3- While feeding the furnace, it is possible that fire catches the wood flow, what is the cheapest way to prevent that?
4- What is the most suitable inclination. I am working on 25, is that good enough. Will it be a problem if i worked on 45degree inclination? Because of space restrictions?
5- For wood chips conveying, what is the most suitable type of material for the hopper, and what is the best type of screw to use (is it standard pitch or helicoidal?)
I am freshly graduated, and i would apreciate your help. Please share with me your knowledges. ■